An ironclad is a naval vessel characterized by protective iron plating.

• A. A wooden sailing ship
• B. A warship protected with iron plating
• C. A light, fast boat
• D. A tank used on land

Answer: (B)

An ironclad is a naval warship that has protective iron plating built into its hull. This armor is the key feature that defines an ironclad, making the ship much harder to damage from cannon fire and signaling a shift from old wooden ships to armored vessels in the 19th century. The other descriptions don’t fit: a wooden sailing ship lacks iron armor, a light, fast boat emphasizes speed over armor, and a tank is designed for land battles, not ships. So the description of a warship protected with iron plating matches what an ironclad is.